fossil

Petrified Wood

Silicified Wood (SiO2)

Hardness: 6.5-7 on Mohs scale. Color: Shades of brown, tan, gray, black, and beige. Luster: Waxy, vitreous, or earthy. Structure: Cryptocrystalline aggregate retaining fibrous cellular wood structures. Cleavage: None (conchoidal fracture). Specific Gravity: 2.6-2.8.

Hardness: 6
Color: Shades of brown, tan, gray, black, and beige
Luster: Waxy, vitreous, or earthy

Identified July 25, 2026More fossil →

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Physical properties

Formation & geological history

Formed when plant material is buried under sediment and water rich in dissolved minerals (usually silica) flows through, replacing the organic plant matter with minerals over millions of years (permineralization), often dating from the Paleozoic to Cenozoic eras.

Uses & applications

Used widely in decorative lapidary arts, jewelry making, bookends, table surfaces, and as highly collectible fossil specimens.

Geological facts

Petrified wood can preserve microscopic cellular details of original ancient trees so clearly that scientists can identify the original species of plant from millions of years ago.

Field identification & locations

Look for visible wood grain, annual tree rings, or fibrous bark-like textures combined with the hardness and weight of stone. Commonly found in ancient riverbeds, sedimentary basins, and volcanic ash deposits nationwide (such as Arizona's Petrified Forest).